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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2011 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: MainClass.html 740 2013-10-02 21:27:31Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.dellroad.stuff.main;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.io.EOFException;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.io.File;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import java.util.ArrayList;<a name="line.12"></a>
<span class="sourceLineNo">013</span><a name="line.13"></a>
<span class="sourceLineNo">014</span>import org.gnu.readline.Readline;<a name="line.14"></a>
<span class="sourceLineNo">015</span>import org.gnu.readline.ReadlineLibrary;<a name="line.15"></a>
<span class="sourceLineNo">016</span>import org.slf4j.Logger;<a name="line.16"></a>
<span class="sourceLineNo">017</span>import org.slf4j.LoggerFactory;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>/**<a name="line.19"></a>
<span class="sourceLineNo">020</span> * Support superclass for command line classes.<a name="line.20"></a>
<span class="sourceLineNo">021</span> */<a name="line.21"></a>
<span class="sourceLineNo">022</span>public abstract class MainClass {<a name="line.22"></a>
<span class="sourceLineNo">023</span><a name="line.23"></a>
<span class="sourceLineNo">024</span>    protected final Logger log = LoggerFactory.getLogger(getClass());<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>    protected MainClass() {<a name="line.26"></a>
<span class="sourceLineNo">027</span>    }<a name="line.27"></a>
<span class="sourceLineNo">028</span><a name="line.28"></a>
<span class="sourceLineNo">029</span>    /**<a name="line.29"></a>
<span class="sourceLineNo">030</span>     * Subclass main implementation. This method is free to throw exceptions; these will<a name="line.30"></a>
<span class="sourceLineNo">031</span>     * be displayed on standard error and converted into non-zero exit values.<a name="line.31"></a>
<span class="sourceLineNo">032</span>     *<a name="line.32"></a>
<span class="sourceLineNo">033</span>     * @return exit value<a name="line.33"></a>
<span class="sourceLineNo">034</span>     */<a name="line.34"></a>
<span class="sourceLineNo">035</span>    public abstract int run(String[] args) throws Exception;<a name="line.35"></a>
<span class="sourceLineNo">036</span><a name="line.36"></a>
<span class="sourceLineNo">037</span>    /**<a name="line.37"></a>
<span class="sourceLineNo">038</span>     * Enter command loop. Commands are read using GNU libreadline and handed off<a name="line.38"></a>
<span class="sourceLineNo">039</span>     * to {@link #handleCommand} for processing.<a name="line.39"></a>
<span class="sourceLineNo">040</span>     */<a name="line.40"></a>
<span class="sourceLineNo">041</span>    protected void commandLoop(String appName, String prompt) throws Exception {<a name="line.41"></a>
<span class="sourceLineNo">042</span><a name="line.42"></a>
<span class="sourceLineNo">043</span>        // Setup readline<a name="line.43"></a>
<span class="sourceLineNo">044</span>        try {<a name="line.44"></a>
<span class="sourceLineNo">045</span>            Readline.load(ReadlineLibrary.GnuReadline);<a name="line.45"></a>
<span class="sourceLineNo">046</span>        } catch (UnsatisfiedLinkError e) {<a name="line.46"></a>
<span class="sourceLineNo">047</span>            // ignore<a name="line.47"></a>
<span class="sourceLineNo">048</span>        }<a name="line.48"></a>
<span class="sourceLineNo">049</span>        Readline.initReadline(appName);<a name="line.49"></a>
<span class="sourceLineNo">050</span>        Readline.setThrowExceptionOnUnsupportedMethod(false);<a name="line.50"></a>
<span class="sourceLineNo">051</span><a name="line.51"></a>
<span class="sourceLineNo">052</span>        // Read init file(s)<a name="line.52"></a>
<span class="sourceLineNo">053</span>        ArrayList&lt;String&gt; files = new ArrayList&lt;String&gt;(3);<a name="line.53"></a>
<span class="sourceLineNo">054</span>        String var = System.getenv("INPUTRC");<a name="line.54"></a>
<span class="sourceLineNo">055</span>        if (var != null)<a name="line.55"></a>
<span class="sourceLineNo">056</span>            files.add(var);<a name="line.56"></a>
<span class="sourceLineNo">057</span>        String home = System.getProperty("user.home");<a name="line.57"></a>
<span class="sourceLineNo">058</span>        if (home != null)<a name="line.58"></a>
<span class="sourceLineNo">059</span>            files.add(new File(new File(home), ".inputrc").getAbsolutePath());<a name="line.59"></a>
<span class="sourceLineNo">060</span>        files.add("/etc/.inputrc");<a name="line.60"></a>
<span class="sourceLineNo">061</span>        for (String file : files) {<a name="line.61"></a>
<span class="sourceLineNo">062</span>            try {<a name="line.62"></a>
<span class="sourceLineNo">063</span>                Readline.readInitFile(file);<a name="line.63"></a>
<span class="sourceLineNo">064</span>            } catch (Exception e) {<a name="line.64"></a>
<span class="sourceLineNo">065</span>                // ignore<a name="line.65"></a>
<span class="sourceLineNo">066</span>            }<a name="line.66"></a>
<span class="sourceLineNo">067</span>        }<a name="line.67"></a>
<span class="sourceLineNo">068</span><a name="line.68"></a>
<span class="sourceLineNo">069</span>        // Read history file<a name="line.69"></a>
<span class="sourceLineNo">070</span>        String historyFile = new File(new File(System.getProperty("user.home")), "." + appName + "_history").getAbsolutePath();<a name="line.70"></a>
<span class="sourceLineNo">071</span>        try {<a name="line.71"></a>
<span class="sourceLineNo">072</span>            Readline.readHistoryFile(historyFile);<a name="line.72"></a>
<span class="sourceLineNo">073</span>        } catch (Exception e) {<a name="line.73"></a>
<span class="sourceLineNo">074</span>            // ignore<a name="line.74"></a>
<span class="sourceLineNo">075</span>        }<a name="line.75"></a>
<span class="sourceLineNo">076</span><a name="line.76"></a>
<span class="sourceLineNo">077</span>        // Main loop<a name="line.77"></a>
<span class="sourceLineNo">078</span>        try {<a name="line.78"></a>
<span class="sourceLineNo">079</span>            while (true) {<a name="line.79"></a>
<span class="sourceLineNo">080</span><a name="line.80"></a>
<span class="sourceLineNo">081</span>                // Read next line<a name="line.81"></a>
<span class="sourceLineNo">082</span>                String line;<a name="line.82"></a>
<span class="sourceLineNo">083</span>                try {<a name="line.83"></a>
<span class="sourceLineNo">084</span>                    line = Readline.readline(prompt);<a name="line.84"></a>
<span class="sourceLineNo">085</span>                } catch (EOFException e) {<a name="line.85"></a>
<span class="sourceLineNo">086</span>                    System.out.println();<a name="line.86"></a>
<span class="sourceLineNo">087</span>                    break;<a name="line.87"></a>
<span class="sourceLineNo">088</span>                }<a name="line.88"></a>
<span class="sourceLineNo">089</span><a name="line.89"></a>
<span class="sourceLineNo">090</span>                // No input?<a name="line.90"></a>
<span class="sourceLineNo">091</span>                if (line == null)<a name="line.91"></a>
<span class="sourceLineNo">092</span>                    continue;<a name="line.92"></a>
<span class="sourceLineNo">093</span><a name="line.93"></a>
<span class="sourceLineNo">094</span>                // Update history<a name="line.94"></a>
<span class="sourceLineNo">095</span>                Readline.addToHistory(line);<a name="line.95"></a>
<span class="sourceLineNo">096</span><a name="line.96"></a>
<span class="sourceLineNo">097</span>                // Execute line<a name="line.97"></a>
<span class="sourceLineNo">098</span>                if (!this.handleCommand(line))<a name="line.98"></a>
<span class="sourceLineNo">099</span>                    break;<a name="line.99"></a>
<span class="sourceLineNo">100</span>            }<a name="line.100"></a>
<span class="sourceLineNo">101</span>        } finally {<a name="line.101"></a>
<span class="sourceLineNo">102</span><a name="line.102"></a>
<span class="sourceLineNo">103</span>            // Save history<a name="line.103"></a>
<span class="sourceLineNo">104</span>            try {<a name="line.104"></a>
<span class="sourceLineNo">105</span>                Readline.writeHistoryFile(historyFile);<a name="line.105"></a>
<span class="sourceLineNo">106</span>            } catch (Exception e) {<a name="line.106"></a>
<span class="sourceLineNo">107</span>                // ignore<a name="line.107"></a>
<span class="sourceLineNo">108</span>            }<a name="line.108"></a>
<span class="sourceLineNo">109</span><a name="line.109"></a>
<span class="sourceLineNo">110</span>            // Clean up<a name="line.110"></a>
<span class="sourceLineNo">111</span>            Readline.cleanup();<a name="line.111"></a>
<span class="sourceLineNo">112</span>        }<a name="line.112"></a>
<span class="sourceLineNo">113</span>    }<a name="line.113"></a>
<span class="sourceLineNo">114</span><a name="line.114"></a>
<span class="sourceLineNo">115</span>    /**<a name="line.115"></a>
<span class="sourceLineNo">116</span>     * Callback used by {@link #commandLoop}.<a name="line.116"></a>
<span class="sourceLineNo">117</span>     *<a name="line.117"></a>
<span class="sourceLineNo">118</span>     * &lt;p&gt;<a name="line.118"></a>
<span class="sourceLineNo">119</span>     * The implementation in {@link MainClass} just returns {@code false}.<a name="line.119"></a>
<span class="sourceLineNo">120</span>     *<a name="line.120"></a>
<span class="sourceLineNo">121</span>     * @return true to continue reading the next command, false to exit<a name="line.121"></a>
<span class="sourceLineNo">122</span>     */<a name="line.122"></a>
<span class="sourceLineNo">123</span>    protected boolean handleCommand(String line) throws Exception {<a name="line.123"></a>
<span class="sourceLineNo">124</span>        return false;<a name="line.124"></a>
<span class="sourceLineNo">125</span>    }<a name="line.125"></a>
<span class="sourceLineNo">126</span><a name="line.126"></a>
<span class="sourceLineNo">127</span>    /**<a name="line.127"></a>
<span class="sourceLineNo">128</span>     * Display the usage message to standard error.<a name="line.128"></a>
<span class="sourceLineNo">129</span>     */<a name="line.129"></a>
<span class="sourceLineNo">130</span>    protected abstract void usageMessage();<a name="line.130"></a>
<span class="sourceLineNo">131</span><a name="line.131"></a>
<span class="sourceLineNo">132</span>    /**<a name="line.132"></a>
<span class="sourceLineNo">133</span>     * Print the usage message and exit with exit value 1.<a name="line.133"></a>
<span class="sourceLineNo">134</span>     */<a name="line.134"></a>
<span class="sourceLineNo">135</span>    protected void usageError() {<a name="line.135"></a>
<span class="sourceLineNo">136</span>        usageMessage();<a name="line.136"></a>
<span class="sourceLineNo">137</span>        System.exit(1);<a name="line.137"></a>
<span class="sourceLineNo">138</span>    }<a name="line.138"></a>
<span class="sourceLineNo">139</span><a name="line.139"></a>
<span class="sourceLineNo">140</span>    /**<a name="line.140"></a>
<span class="sourceLineNo">141</span>     * Emit an error message an exit with exit value 1.<a name="line.141"></a>
<span class="sourceLineNo">142</span>     */<a name="line.142"></a>
<span class="sourceLineNo">143</span>    protected final void errout(String message) {<a name="line.143"></a>
<span class="sourceLineNo">144</span>        System.err.println(getClass().getSimpleName() + ": " + message);<a name="line.144"></a>
<span class="sourceLineNo">145</span>        System.exit(1);<a name="line.145"></a>
<span class="sourceLineNo">146</span>    }<a name="line.146"></a>
<span class="sourceLineNo">147</span><a name="line.147"></a>
<span class="sourceLineNo">148</span>    /**<a name="line.148"></a>
<span class="sourceLineNo">149</span>     * Parse command line flags of the form {@code -Dname=value} and set the corresponding system properties.<a name="line.149"></a>
<span class="sourceLineNo">150</span>     * Parsing stops at the first argument not starting with a dash (or {@code --}).<a name="line.150"></a>
<span class="sourceLineNo">151</span>     *<a name="line.151"></a>
<span class="sourceLineNo">152</span>     * @return command line with all the property-setting flags removed<a name="line.152"></a>
<span class="sourceLineNo">153</span>     */<a name="line.153"></a>
<span class="sourceLineNo">154</span>    protected String[] parsePropertyFlags(String[] args) {<a name="line.154"></a>
<span class="sourceLineNo">155</span>        ArrayList&lt;String&gt; list = new ArrayList&lt;String&gt;(args.length);<a name="line.155"></a>
<span class="sourceLineNo">156</span>        boolean done = false;<a name="line.156"></a>
<span class="sourceLineNo">157</span>        for (String arg : args) {<a name="line.157"></a>
<span class="sourceLineNo">158</span>            if (done) {<a name="line.158"></a>
<span class="sourceLineNo">159</span>                list.add(arg);<a name="line.159"></a>
<span class="sourceLineNo">160</span>                continue;<a name="line.160"></a>
<span class="sourceLineNo">161</span>            }<a name="line.161"></a>
<span class="sourceLineNo">162</span>            if (arg.equals("--") || arg.length() == 0 || arg.charAt(0) != '-') {<a name="line.162"></a>
<span class="sourceLineNo">163</span>                list.add(arg);<a name="line.163"></a>
<span class="sourceLineNo">164</span>                done = true;<a name="line.164"></a>
<span class="sourceLineNo">165</span>                continue;<a name="line.165"></a>
<span class="sourceLineNo">166</span>            }<a name="line.166"></a>
<span class="sourceLineNo">167</span>            if (arg.startsWith("-D")) {<a name="line.167"></a>
<span class="sourceLineNo">168</span>                int eq = arg.indexOf('=');<a name="line.168"></a>
<span class="sourceLineNo">169</span>                if (eq &lt; 3)<a name="line.169"></a>
<span class="sourceLineNo">170</span>                    usageError();<a name="line.170"></a>
<span class="sourceLineNo">171</span>                System.setProperty(arg.substring(2, eq), arg.substring(eq + 1));<a name="line.171"></a>
<span class="sourceLineNo">172</span>                continue;<a name="line.172"></a>
<span class="sourceLineNo">173</span>            }<a name="line.173"></a>
<span class="sourceLineNo">174</span>            list.add(arg);<a name="line.174"></a>
<span class="sourceLineNo">175</span>        }<a name="line.175"></a>
<span class="sourceLineNo">176</span>        return list.toArray(new String[list.size()]);<a name="line.176"></a>
<span class="sourceLineNo">177</span>    }<a name="line.177"></a>
<span class="sourceLineNo">178</span><a name="line.178"></a>
<span class="sourceLineNo">179</span>    /**<a name="line.179"></a>
<span class="sourceLineNo">180</span>     * Invokes {@link #run}, catching any exceptions thrown and exiting with a non-zero<a name="line.180"></a>
<span class="sourceLineNo">181</span>     * value if and only if an exception was caught.<a name="line.181"></a>
<span class="sourceLineNo">182</span>     * &lt;p/&gt;<a name="line.182"></a>
<span class="sourceLineNo">183</span>     * &lt;p&gt;<a name="line.183"></a>
<span class="sourceLineNo">184</span>     * The concrete class' {@code main()} method should invoke this method.<a name="line.184"></a>
<span class="sourceLineNo">185</span>     * &lt;/p&gt;<a name="line.185"></a>
<span class="sourceLineNo">186</span>     */<a name="line.186"></a>
<span class="sourceLineNo">187</span>    protected void doMain(String[] args) {<a name="line.187"></a>
<span class="sourceLineNo">188</span>        int exitValue = 1;<a name="line.188"></a>
<span class="sourceLineNo">189</span>        try {<a name="line.189"></a>
<span class="sourceLineNo">190</span>            exitValue = run(args);<a name="line.190"></a>
<span class="sourceLineNo">191</span>        } catch (Throwable t) {<a name="line.191"></a>
<span class="sourceLineNo">192</span>            t.printStackTrace(System.err);<a name="line.192"></a>
<span class="sourceLineNo">193</span>        } finally {<a name="line.193"></a>
<span class="sourceLineNo">194</span>            System.exit(exitValue);<a name="line.194"></a>
<span class="sourceLineNo">195</span>        }<a name="line.195"></a>
<span class="sourceLineNo">196</span>    }<a name="line.196"></a>
<span class="sourceLineNo">197</span>}<a name="line.197"></a>
<span class="sourceLineNo">198</span><a name="line.198"></a>




























































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